1998 FIAT PUNTO ESP

7A*2 Manual transmission
Gear selection is via a floor-mounted lever and selector rod mechanism (seo Illustration). The selector rod causes the appropriate selector fork to move its respective synchro-sleeve along the shaft, to lock the gear to the synchro-hub. Since the synchro-hubs are splined to the Input and output shafts, this locks the gear to the shaft, so that drive can be transmitted. To ensure that gear-changing can be made quickly and quietly, a synchro-mesh system Is fitted to all forward gears,
2 Gearchange lever and linkage -
removal and refitting ^
Removal 1 Firmly apply the handbrake, then jack up the front of the car and support It securely on axle stands {see Jacking and veh/cte support). 2 Remove the exhaust system with reference to Chapter 4D.
3 Unbolt the exhaust heatshield and remove It from under the vehicle. 4 Disconnect the gearchange cable and rod from the transmission and from the body. Also disconnect the reverse inhibitor cable. 5 Unscrew the single screw and remove the centre console from inside the vehicle. 6 Unscrew the front mounting securing the gearchange lower cover to the body. 7 Under Ihe vehicle unscrew the lower cover mounting bolts, then lower Ihe assembly and remove from under the vehlole. 8 The gearchange lever may be removed by disconnecting the cables and removing the pivot bolt. Note the location of the spacers and washers to ensure correct reassembly. If necessary the bushes may be renewed by unscrewing the mounting nuts. 9 Reassembly is a reversal of dismantling but apply a little multi-purpose grease to the bearing surfaces.
Refitting 10 Refitting is a reversal of removal. Tighten all nuts and bolts securely.
3 Manual transmission - & removal and refitting § S
Petrol models
Removal 1 Select a solid, level surlace to park the vehicle upon. Give yourself enough space to move around it easily. Apply the handbrake then jack up the front of the vehicle and support on axle stands (see Jacking and vehicle support). Remove both front wheels. 2 Disconnect the wiring connectors from (he anti-theft alarm located next to the battery, then unbolt and remove the alarm. 3 Remove the battery and mounting tray as described in Chapter 5A. 4 Disconnect the wiring from the reversing light switch on the front of the transmission. 5 Unscrew the nut and disconnect the earth cable from its stud. 6 On models with a cable operated clutch,
1.4 Gearchange lever and linkage 1 Gear lever sliding part 3 Gear selector control rod 5 Gear selector link rod 2 Reverse gear inhibition 4 Gear engagement control 6 Gear selector control rod cable cable 7 Reverse gear inhibition device

I
8*4 Driveshafts
3.3 Using pair of circlip pliers, expand the circlip that holds the driveshaft in place
Turbo diesel models 4 Mark the relationship between the joint and the driveshaft using a scriber or a dab of paint. Attach a slide hammer to the dnveshaft nut thread. 5 Draw the joint off the driveshaft using the slide hammer, Use just enough effort to overcome the tension of the internal circlip.
Inboard CV joint removal All models except turbo dieseis 6 Al the inboard end of the driveshaft. use a hammer and centre punch to mark the relationship between Ihe shaft and |olnt. Remove the circlip with a pair of circlip pliers, then using a three-legged puller if required, draw Ihe tripod joint off the end of the driveshaft. Ensure that the legs of Ihe puller bear upon the cast centre section of the joint, not the roller beanngs (see illustration) Turbo diesel models 7 Al the inboard end of Ihe driveshaft. use a hammer and centre punch lo mark the relationship between the shaft and joint. Remove the circlip with a pair of circlip pliers, then carefully slide the CV joint from the end ot the shaft. Take great care to prevenl the
cage and bail bearings from falling out • secure the joint components together with wire or a nylon cable-tie. 8 Remove the washer then slide the flange from the end of the shaft.
Inspection 9 Slide both rubber gaiters off the driveshaft and discard them: It is recommended that new ones are fitted on reassembly as a matter of course. Recover the flexible washers (where fitted), making a note of their fitted positions, to aid correct refitting later. 10 Thoroughly clean the driveshaft splines, and CV joint components with paraffin or a suitable solvent, taking care not to destroy any alignment marks made during removal. 11 Examine Ihe CV joint components for wear and damage: in particular, check the balls and corresponding grooves for pitting and corrosion. If evidence of wear Is visible, then the joint must be renewed. Note that if the outboard CV joint Is to be renewed on turbo diesel models, it must be matched to the driveshaft using the colour-coded paint markings. 12 Where applicable, examine the tripod joint components for wear. Check thai the three rollers are free lo rotate without resistance and are not worn, damaged or corroded. The rollers are supported by arrays of needle bearings: wear or damage will show up as play In the rollers and/or roughness in rotation. If wear is discovered, the tnpod joint must be renewed. 13 Fit a new rubber gaiter (and where applicable, flexible washer) to the inboard end of the driveshaft and secure it In place on the shaft with a clip (see illustration).
Inboard CV joint - refitting
All models except turbo dieseis 14 Using Ihe alignment marks made during removal, fit the tripod joint onto the splines of the driveshaft. Tap It Into position using a soft faced mallet. To ensure that the tripod Joint rollers and driveshaft splines are not damaged, use a socket with an internal diameter slightly larger than I hat of the driveshafl as a drift. Refit the circlip. 15 Slide the gaiter over tho tripod joint and pack the gaiter with grease from the service kit.
3.6 Draw the tripod joint off the end of the driveshaft 3.13 FH s new rubber gaiter to the inboard end of the driveshaft and secure It in place with a clip
Caution: Do not allow grease to come
into
contact with vehicles paintwork, es discolouring may rasutt. Turbo diesel models 16 Slide the flange and washer onto the end of the shaft, then fit the joint Into position on the driveshaft splines, using the alignment marks made during removal. Fit the circlip. ' 17 Pack the gaiter with grease from His service kit, then slide the gaiter over the joint. Briefly lift the lip of the gaiter to expel ail the air from the joint, then secure the gaiter over the joint with a new clip. Caution: Do not allow grease to come
Into
contact with the vehicle's paintwork, as discolouring may result.
Outboard CV joint - refitting 18 Fit a new rubber gaiter to the outboard end of the driveshaft and secure it place with a dp, 19 Pack the CV joint with grease from Ihe service kit, pushing It into the ball grooves and expelling any air that may be trapped underneath. 20 Lubricate the splines of the drive shaft with a smear of grease, then whilst splaying the circlip open with a pair ot circlip pile*, insert the driveshaft into CV joint, observing the alignment marks made during removal. Note: On turbo diesel models, the circlip snaps into the CV Joint groove as Ifte driveshaft is inserted - no circlip pliers are required. Ensure that the circlip snaps securely Into place: pull on the shaft to check that it is held firmly In position. 21 Pack additional grease Into the joint to displace any air pockets, then slide the rubber gaiter over the joint. Briefly lift the lip ol the gaiter to expel all the air from Ihe joint, then secure it In place with a clip. 22 Refit the driveshaft (see Section 2).
4 Intermediate driveshaft - % removal and refitting J;
Note 1: This procedure applies only to turbo diesel engined models. Note 2: The intermediate shaft and
bearing
are not available as separate spares and cac only be renewed as a comptefe assembly.
Removal 1 Firmly apply the handbrake, then jack up the front of Ihe car and support It securely
on
axle stands (see Jacking and vehicle support). Remove the appropriate roadwheei(s). 2 Unbolt the inboard end of the right*hand driveshaft from the intermediate shaft
flange, as
described In Section 2. Suspend the dis-connected end of the driveshaft from a conven-ient point on the subframe, using wire or a cable-tie. to avoid straining the joint and gaiter. 3 Drain the oil from the transmission, with reference to Chapter 1B.

Suspension and steering 10*13
the skill required to use It properly, the checking and adjustment of these settings Is best left to a Fiat dealer or similar expert. Most tyre-fitting shops now possess sophisticated checking equipment. 3 For accurate checking, the vehicle must be at the kerb weight specified in Dimensions and weights. 4 Before starting work, check first that the tyre sizes and types are as specified (see Tyre pressures in Weekly checks), then check tyre pressures and tread wear. Also check roadwheel run-out, the condition of the hub bearings, the steering wheel free play and the condition of the front suspension components (Steering and suspension check in Chapter 1A or
1B).
Correct any faults found. 6 Park the vehicle on level ground, with the front roadwheeis in the straight-ahead position. Rock the rear and front ends to settle the suspension. Release the handbrake and roll the vehicle backwards approximately 1 metre, then forwards again, to relieve any stresses in the steering and suspension components. 6 Two methods are available to the home mechanic for checking the front wheel toe setting. One method is to use a gauge to measure the distance between the front and rear inside edges of the roadwheeis. The other method is to use a scuff plate, in which each front wheel is rolled across a movable plate which records any deviation, or scuff, of the tyre from the straight-ahead position as It moves across the plate. Such gauges are available in relatively-inexpensive form from accessory outlets. It Is up to the owner to decide whether the expense is justified, In view of the small amount of use such equipment would normally receive. 7 Prepare the vehicle 8S described in paragraphs 3 to 5 above.
8 If the measurement procedure is being used, carefully measure the distance between the front edges of the roadwheel rims and the rear edges of the rims. Subtract the front measurement from the rear measurement, and check that the result is within the specified range. If not, adjust the toe setting as described in paragraph 10. 9 If scuff plates are to be used, roll the vehicle backwards, check that the roadwheeis are in the straight-ahead position, then roll it across the scuff plates so that each front roadwheel passes squarely over the centre of its respective plate. Note the angle recorded by the scuff plates. To ensure accuracy, repeat the check three times, and take the average of the three readings, if the roadwheeis are running parallel, there will of course be no angle recorded; If a deviation value Is shown on the scuff plates, compare the reading obtained for each wheel with that supplied by the scuff plate manufacturers. If the value recorded is outside Ihe specified tolerance, the toe setting is incorrect, and must be adjusted as follows. Adjustment 10 Apply the handbrake, then jack up the front of the vehicle and support it securely on axle stands (see Jacking and vehicle support). Turn the steering wheel onto full-left lock, and record the number of exposed threads on the right-hand track-rod. Now turn the steering onto full-right lock, and record the number of threads on the left-hand side. If there are the same number of threads visible on both sides, then subsequent adjustment should be made equally on both sides. If there are more threads visible on one side than the other, it will be necessary to compensate for this during adjustment Note: It is important to ensure that, after adjustment, the same number of threads are visible on the end of each track-rod.
11 First clean the track-rod threads; If they are corroded, apply penetrating fluid before starting adjustment. Release the steering gear rubber gaiter outboard clips, then peel back the gaiters and apply a smear of grease, so that both gaiters are free and will not be twisted or strained as their respective track-rods are rotated. 12 Use a straight-edge and a scriber or similar to mark the relationship of each track-rod to the track-rod end. Working on each track-rod end in tum, unscrew its locking nut. 13 Alter the length of the track-rods, bearing In mind the note in paragraph 10, by screwing them into or out of the track-rod ends. Rotate the track-rod using an open-ended spanner fitted to the flats provided. If necessary, counterhold the track-rod end using a second spanner. Shortening the track-rods (screwing them Into their track-rod ends) will reduce toe-in and increase toe-out. 14 When the setting Is correct, hold the track-rods and securely tighten the locking nuts. Check that the balljoints are seated correctly In their sockets, and count the exposed threads on the ends of the track-rods. If the number of threads exposed is not the same on both sides, then the adjustment has not been made equally, and problems will be encountered with tyre scrubbing in turns; also, the steering wheel spokes will no longer be horizontal when the wheels are in the straight-ahead position. 15 When the track-rod lengths are the same, lower the vehicle to the ground and re-check the toe setting; readjust if necessary. When the setting is correct, tighten the locking nuts. Ensure that the steering gear rubber gaiters are seated correctly and are not twisted or strained, then secure them In position with new retaining clips.
10

11 *2 Bodywork and fittings
on vehicles with wax-based underbody protective coating, or the coating will be removed. Such vehicles should be inspected annually, preferably just prior lo Winter, when the underbody should be washed down, and any damage to the wax coating repaired. Ideally, a completely fresh coat should be applied. It would also be worth considering the use of such wax-based protection for injection into door panels, sills, box sections, etc, as an additional safeguard against rust damage, where such protection Is not provided by the vehicle manufacturer. After washing paintwork, wipe off with a chamois feather to give an unspotted clear finish. A coat of clear protective wax polish wilt give added protection against chemical pollutants in the air. If the paintwork sheen has duiled or oxidised, use a cleaner/polisher combination to restore the brilliance of the shine. This requires a little effort, but such dulling Is usually caused because regular washing has been neglected. Care needs to be taken with metallic paintwork, as special non-abrasive cleaner/polisher is required to avoid damage to the finish, Always check that the door and ventilator opening drain holes and pipes are completely clear, so that water can be drained out. Brightwork should be treated In the same way as paintwork. Windscreens and windows can be kept clear of the smeary film which often appears, by the use of proprietary glass cleaner. Nover use any form of wax or other body or chromium polish on glass.
Maintenance -upholstery and carpets
Mats and carpets should be brushed or vacuum-cleaned regularly, to keep them free of grit. If they are badly stained, remove them from the vehicle for scrubbing or sponging, and make quite sure they are dry before refitting. Seats and interior trim panels can be kept clean by wiping with a damp cloth. If they do become stained (which can be more apparent on light-coloured upholstery), use a little liquid detergent and a soft nail brush lo scour the grime out of the grain of the material. Do not forget to keep the headlining clean in the same way as the upholstery. When using liquid cleaners inside the vehicle, do not over-wet the surfaces being cleaned. Excessive damp could get Into the seams and padded interior, causing stains, offensive odours or even rot.
If the Inside of the vehicle gets wet accidentally, tt Is worthwhile taking some trouble to dry ft out property, particularly where carpets an involved. Do not leave oil or electric heaters inside the vehicle for this purpose.
4 Minor body damage -repair
Repairs of minor scratches In bodywork If the scratch Is very superficial, and does not penetrate to the metal of the bodywork, repair is very simple. Lightly rub the area of the scratch with a paintwork renovator, or a very fine cutting paste, to remove loose paint from the scratch, and to clear the surrounding bodywork of wax polish, Rinse the area with clean water. Apply touch-up paint to ihe scratch using a fine paint brush; continue to apply fine layers of paint until the surface of the paint In the scratch Is level with the surrounding paintwork. Allow Ihe new paint at least two weeks to harden, then blend it Into the surrounding paintwork by rubbing the scratch area with a paintwork renovator or a very fine cutting paste. Finally, apply wax polish. Where the scratch has penetrated right through to the metal of the bodywork, causing the metal to rust, a different repair technique Is required. Remove any loose rust from the bottom of the scratch with a penknife, then apply rust-inhibiting paint to prevent the formation of rust in the future. Using a rubber or nylon applicator, fill the scratch with bodystopper paste. If required, this paste can be mixed with cellulose thinners to provide a very thin paste which is ideal for filling narrow scratches. Before the stopper-paste in Ihe scratch hardens, wrap a piece of smooth cotton rag around the top of a finger. Dip the finger in cellulose thinners, and quickly sweep it across the surface of the stopper-paste in the scratch: this will ensure that the surface of the stopper-paste is slightly hollowed. The scratch can now be painted over as described earlier In this Section.
Repairs of dents in bodywork When deop denting of the vehicle's bodywork has taken place, the first task is to put) the dent out. until the affected bodywork almost attains rts onginal shape. There is little polnl in trying to restore Ihe original shape completely, as the metal in the damaged area will have stretched on impact, and cannot be reshaped fully to its original contour. It Is better to bring the level of the dent up to a point which is about 3 mm below the level of the surrounding bodywork. In cases where Ihe dent is very shallow anyway, It is not worth trying to pull it out at all. If the underside of the dent is accessible, it can be hammered out gently from behind, using a mallet with a wooden or plastic head, Whilst doing this, hold a suitable block of wood firmly against (he outside of Ihe panel, to absorb the impact from the hammer blows and thus prevent a large area of the bodywork from being 'belled-out".
Should the dent be In a section of (I* bodywork which has a double skin, or seme other factor making It Inaccessible from behind, a different technique is called for. Dull several small holes through the metal inside Ihe area - particularly in the deeper section. Then screw long self-tapping screws Into the holes, just sufficiently for them to gain a good purchase in the metal. Now the dent can be pulled out by pulling on the protruding heads of the screws with a pair of pliers. The next stage of the repair Is the removal of the paint from the damaged area, and from an inch or so of the surrounding 'sound' bodywork. This is accomplished most easily by using a wire brush or abrasive pad on a posver drill, although it can be done just as effectively by hand, using sheets of abrasive paper. To complete the preparation for filling, score the surface of the bare metal wflhi screwdriver or the tang of 8 file, or alternatively, drill small holes In the affected area. This will provide a really good 'key' for the filler paste. To complete the repair, see the Section on filling and respraying.
Repairs of rust holes or gashes in bodywork Remove all paint from the affected area, and from an inch or so of the surrounding 'sound' bodywork, using an abrasive pad
or a
wire brush on a power drill. If these are not available, a few sheets of abrasive paper wil do the job most effectively. With the paint removed, you will be able to judge the severity of the corrosion, and therefore decide whether to renew the whole panel (if this is possible) or to repair the affected area. New body panels are not as expansive as most people think, and it is often quicker and more satisfactory to fit a new panel than to attempt to repair large areas of corrosion. Remove all fittings from Ihe affected area, except those which will act as a guide to ttie original shape of the damaged bodywork (eg headlight shells etc). Then, using tin snips
or a
hacksaw blade, remove all loose metal snd any other metal badly affected by corrosion. Hammer the edges of the hole inwards, in order to create a slight depression for the filer paste. Wire-brush the affected area to remove tha powdery rust from the surface of the remaining metal. Paint Ihe affected area with rust-inhibiting paint, if the beck of the rusted area is accessible, treat this also. Before filling can take place, ft will be necessary to block the hole in some
way.
TNs can be achieved by the use of aluminium cr plastic mesh, or aluminium tape. Aluminium or plastic mesh, or glass-fibre matting, is probably the best material to use for a large hole. Cut a piece to tha approximate size and shape of tho hole to b« filled, then position it In the hole so that its edges are below the level of the surrounding bodywork. It can be retained in position by

Bodywork and fittings
11
*3
several blobs of filler paste around its periphery. Aluminium tape should be used for small or very narrow holes. Pull a piece off the roll, trim it to the approximate size and shape required, then pull off the backing paper (if used) and stick the tape over the hole; it can be overlapped if the thickness of one piece is Insufficient. Burnish down the edges of the tape with the handle of a screwdriver or similar, to ensure that the tape is securely attached to the metal underneath.
Bodywork repairs -filling and respraying Before using this Section, see the Sections on dent, deep scratch, rust holes and gash repairs. Many types of bodyfiller are available, but generally speaking, those proprietary kits which contain a tin of filler paste and a tube of resin hardener are best for this type of repair. A wide, flexible plastic or nylon applicator will be found invaluable for imparting a smooth and well-contoured finish to the surface of the filler. Mix up a little filler on a clean piece of card or board • measure the hardener carefully (follow the maker's instructions on the pack), otherwise the filler will set too rapidly or too slowly. U3ing the applicator, apply the filler paste to the prepared area; draw the applicator across the surface of the filler to achieve the correct contour and to level the surface. As soon as a contour that approximates to the correct one is achieved, stop working the paste - if you carry on too long, the paste will become sticky and begin lo 'pick-up' on the applicator. Continue to add thin layers of filler paste at 20-minute Intervals, until the level of the filler is just proud of the surrounding bodywork. Once the filler has hardened, the excess can be removed using a metal plane or file. From then on, progressively-finer grades of abrasive paper should be used, starting with a 40-grade production paper, and finishing with a 400-grade wet-and-dry paper. Always wrap the abrasive paper around a flat rubber, cork, or wooden block • otherwise the surface of the filler will not be completely flat. During the smoothing of the filler surface, the wet-and-dry paper should be periodically rinsed in water. This will ensure that a very smooth finish is imparled to the filler at the final stage. At this stage, the dent should be surrounded by a ring of bare metal, which in turn should be encircled by the finely feathered' edge of the good paintwork. Rinse the repair area with clean water, until all of the dust produced by the rubbing-down operation has gone. Spray the whole area with a light coat of primer - this will show up any imperfections In the surface of the filler. Repair these imperfections with fresh filler paste or bodystopper, and once more smooth the surface with abrasive paper. Repeat this
spray-and-repair procedure until you are satisfied that the surface of the filler, and the feathered edge of the paintwork, are perfect. Clean the repair area with clean water, and allow to dry fully.
flflfl^gl tf txxfystopper is used, it can WiMiiBi be mixed with cellulose Hi NT thinners to form a really thin 1 1 paste which is Ideal for filling small holes.
The repair area Is now ready for final spraying. Paint spraying must be carried out in a warm, dry, windless and dust-free atmosphere. This condition can be created artificially if you have access to a large indoor working area, but If you are forced to work in the open, you will have to pick your day very carefully. If you are working indoors, dousing the floor In the work area with water will help to settle the dust which would otherwise be in the atmosphere. If the repair area is confined to one body panel, mask off the surrounding panels; this will help to minimise the effects of a slight mis-match in paint colours. Bodywork fittings (eg chrome strips, door handles etc) will also need to be masked off. Use genuine masking tape, and several thicknesses of newspaper, for the masking operations. Before commencing to spray, agitate the aerosol can thoroughly, then spray a test area (an old tin. or similar) until the technique is mastered. Cover the repair area with a thick coat of primer; the thickness should be built up using several thin layers of paint, rather than one thick one. Using 400-grade wet-and-dry paper, rub down the surface of the pnmer until it is really smooth. While doing this, the work area should be thoroughly doused with water, and the wet-and-dry paper periodically rinsed in water. Allow to dry before spraying on more paint. Spray on the top coat, again building up the thickness by using several thin layers of paint. Start spraying at one edge of the repair area, and then, using a side-to-side motion, work until the whole repair area and about 2 inches of the surrounding original paintwork is covered. Remove all masking material 10 to 15 minutes after spraying on the final coat of paint. Allow the new paint at least two weeks to harden, then, using a paintwork renovator, or a very fine cutting paste, blend the edges of the paint into the existing paintwork. Finally, apply wax polish.
Plastic components With the use of more and more plastic body components by the vehicle manufacturers (eg bumpers, spoilers, and in some cases major body panels), rectification of more serious damage to such items has become a matter of either entrusting repair work to a specialist in this field, or renewing complete components. Repair of such damage by the
DIY owner is not really feasible, owing to the cost of the equipment and materials required for effecting such repairs. The basic technique involves making a groove along the line of the crack in the plastic, using a rotary burr In a power drill. The damaged part is then welded back together, using a hot-air gun to heat up and fuse a plastic filler rod Into the groove. Any excess plastic is then removed, and the area rubbed down to a smooth finish. It is important that a filler rod of the correct plastic is used, as body components can be made of a variety of different types (eg polycarbonate, ABS, polypropylene). Damage of a less senous nature (abrasions, minor cracks etc) can be repaired by the DIY owner using a two-part epoxy filler repair material. Once mixed in equal proportions, this is used in similar fashion to the bodywork filler used on metal panels. The filler is usually cured in twenty to thirty minutes, ready for sanding and painting. If the owner is renewing a complete component himself, or If he has repaired it with epoxy filler, he will be left with the problem of finding a suitable paint for finishing which is compatible with the type of plastic used. At one time, the use of a universal paint was not possible, owing to the complex range of plastics encountered In body component applications. Standard paints, generally speaking, will not bond to plastic or rubber satisfactorily. However, it is now possible to obtain a plastic body parts finishing kit which consists of a pre-pnmer treatment, a primer and coloured top coat. Full Instructions are normally supplied with a kit, but basically, the method of use is to first apply the pre-pnmer to the component concerned, and allow It to dry for up to 30 minutes. Then the primer is applied, and left to dry for about an hour before finally applying the special-coloured top coat. The result is a correctly-coloured component, where the paint will flex with the plastic or rubber, a property that standard paint does not normally possess.
5 Major body damage -repair
Where serious damage has occurred, or large areas need renewal due to neglect, it means that complete new panels will need welding-in, and this is best left to professionals. If the damage is due to Impact, it will also be necessary to check completely the alignment of the bodyshell, and this can only be carried out accurately by a Fiat dealer using special jigs. If the alignment of the bodyshell is not corrected, the car's handling may be seriously affected. In addition, excessive stress may be Imposed on the steering, suspension, tyres or transmission, causing abnormal wear or even complete failure.

12*2 Body electrical systems
3 Electrical problems usually stem from simple causes, such as loose or corroded connections, a faulty earth connection, a blown fuse, a melted lusible link, or a fautty relay {refer to Section 3 for details of testing relays). Visually inspect the condition of all (uses, wires and connections in a problem circuit before testing the components. Use the wiring diagrams lo determine which terminal connections will need to be checked, in order to pinpoint the trouble-spot. 4 The basic tools required for electrical fault-finding include a circuit tester or voltmeter (a 12-volt bulb with a set of lest leads can also be used for certain tests}; a self-powered test light (sometimes known as a continuity tester); an ohmmeter (to measure resistance): a battery and set of tesi leads: and a lumper wire, preferably with u circuit breaker or fuse incorporated, which can be used to bypass susoect wires or electrical components. Before attempting to locate a problem with tost instruments, use the wiring diagram to determine where to make the connections. 5 To find the source of an intermittent wiring fault (usually due to a poor or dirty connection, or damaged wiring Insulation), a wiggle test can be performed on the wiring. This involves wiggling the wiring by hand, to see if tha fault occurs as the wiring Is moved. It should be possible to narrow down the source of the fault to a particular section of wiring. This method of testing can be used in conjunction with any of the tests descnbed in the following sub-Sections. 6 Apart from problems due to poor connections, two basic types of fault can occur in an electrical circuit - open-circuit, or short-circuit. 7 Open-circuit faults are caused by a break somewhere in the circuit, which prevents current from flowing. An open-circuit fault will prevent a component from working, but will not cause the relevant circuit fuse to blow 8 Short-circuit faults are caused by a shod somewhere in the circuit, which allows Die current flowing In the circuit to escape along an alternative route, usually to earth. Short-circuit faults are normally caused by a breakdown in wiring insulation, which allows a feed wire to touch either another wire, or an earthed component such as the bodysheli. A short-circuit fault will normally cause the relevant circuit fuse to blow.
Finding an open-circuit 9 To check for an opon-circuit, connect one lead of a circuit tester or voltmoter to either the negative battery terminal or a known good earth. 10 Connect the other lead to a connector in the circuit being tested, preferably nearest to the batter/ or luse. 11 Switch on the circuit, bearing In mind that some circuits are live only when tho ignition switch is moved to a particular position. 12 If voltage is present (Indicated either by
3.2 Main fuse box, located on the driver's side of the facie the toster bulb lighting or a voltmeter reading, as applicable), this means that tho section of Ihe circuit between the relevant connector and the battery is problem-free. 13 Continue to check the remainder ot the circuit in the same fashion. 14 When a point is reached at which no voltage Is present, the problem must lie between that point and the previous test point with voltage. Most problems can be traced to a broken, corroded or loose connection.
Finding a short-circuit 15 To check for a short-circuit, first disconnect the load(s) from the circuit (loads are the components which draw current from a circuit, such as bulbs, motors, heating elements, etc). 16 Remove the relevant luse Irom the circuit, and connect a circuit tester or voltmeter to the luse connections. 17 Switch on the circuit, beanng in mind that some circuits are live only when the ignition switch is moved to a particular position. 18 If voltage is present (indicated either by the tester bulb lighting or a voltmeter reading, as applicable), this means that there Is a short-circuit. 19 If no voltage is present, but the fuse still blows with the load(s) connected, this indicates an internal fault in the load(s).
Finding an earth fault 20 The battery negative terminal Is connected to 'earth' - the metal of the engine/transmission and the car body - and
I
IK
J 3.3 To gain access to the fuses, remove the screw and pull the stowage bin away from the facia
most systems are wired so that they only receive a positive feed, the current returning via the metal of Ihe car body. This means that the component mounting and the body form part of that circuit. Loose or corroded mountings can therefore cause a range of electrical faults, ranging from total failure ot a circuit, to a puzzling partial fault. In particular, lights may shine dimly (especially when another circuit sharing the same earth port In operation), motors (eg wiper motors v Ihe radiator cooling fan motor) may run slowly, and Ihe operation of one circuit may have an apparently-unrelated effect on another. Ncie that on many vehicles, earth straps axe uses between certain components, such as the engine/transmission and the body, usually whore there is no metal-to-metal contact between components, due to flexible rubber mountings, etc. 21 To check whether a component $ properly earthed, disconnect Ihe battery, and connect one lead of an ohmmeter to a kwwi good earth point. Connect the other lead to the wire or earth connection being tested. Tha resistance reading should be zero; if not. check the connection as follows. 22 If an earth connection Is thought to be faulty, dismantle the connection, and clean pack to bare metal both the bodysheli and ite wire terminal or the component earth connection mating surface. Be careful to remove all traces of dirt and corrosion, then use a knife to trim away any palm, so thai a clean metal-to-metal joint Is mads. On reassemoly, tighten the joint fasteners securely: if a wire terminal Is being refitted, use serrated washers between tho terminal and the bodysheli. to ensure a clean and secure connection. When the connection is remade, prevent the onset ot corrosion in the future by applying a coat of petroleum idly
or
stlicone-based grease, or by spraying on (a: regular intervals} a proprietary ignition eoater, or a water-aispersant lubneant.
3 Fuses and relays -general information
Fuses 1 Fuses are designod to break a circuit when a predetermined current is reached, in order to protect the components and wiring wttioh could be damaged by excessive current How. Any excessive current flow will be due to a fault in the circuit, usually a short-circuit (see Section 2). 2 The main fuses are located in the fusefcox on the driver's side of the facia (see illustration). 3 To gain access to the fuses, remove tne screw and pull the stowage bin moulding away from the facia (see illustration). 4 Additional fuses and circuit-breakers are located In the engine compartment, and in an